Puzzle

As I have a public footpath running the length of my garden I installed CCTV several years ago. Not relying on the system to report faults on itself, I have a Raspberry Pi that monitors it externally. Today, that paid off as the main recorder was no longer recording correctly. 
It took some investigation to find that somewhere deep inside some corruption had occurred. Slowly working through the configuration I found nothing wrong, but after making some test changes, and then restoring the items to their previous values all came good. A couple of hours and it was all working correctly again.
That's one way to spend a wet Saturday morning.